1. Field of the Invention
The present invention relates to security keys, for example key cards and magnetic badges, and methods for using them.
2. Description of Related Art
Keys, cards, or tickets with encoded secure access information are increasingly used to secure access to facilities, materials and equipment, and at the point of payment or delivery for commercial transactions. Such keys often comprise a physical article, such as a badge or ticket, that includes a secure access code in a magnetic or optical form. The keys are encoded with a secure access code using a suitable encoding device, such as a magnetic writing device. Often, the access code is encrypted for greater security. The access code is stored in a database and the physical key is distributed to the authorized user. At the point of access control to the facility or equipment, a key reader reads the encoded secure access code, decrypts it if necessary, and compares it to a database of access codes. An appropriate level of access may then be determined based on the comparison.
Such keys may be used to grant access to a location, materials or equipment for an indeterminate amount of time, for a determined period of time or for a defined amount of use, or for a defined number of visits. For example, a key card for access to a building or secured facility are commonly used in access control systems. A single-use ticket for access to a specific event may also be considered as a type of key, when the ticket is authenticated using a secure code carried by the ticket. Further applications for keys using secure access codes may include debit cards for various purposes, such as fare cards for rapid transit, video arcades, self-service laundromats, and other automated or semi-automated vending applications. In addition to bearing an identification code, some types of debit cards may be used to keep track of an account balance. All of these applications may be considered applications of access control systems using secure access codes.
Such access control systems are subject to certain limitations. For one, encoding a new key, or updating information on an existing key, requires that the card be returned to a suitable encoding device. This may make it difficult to provide an access control system that that can rapidly adjust to changed circumstances, or that can service users lacking access to a secure encoding device. In addition, both encoding devices and key readers should be connected to a common database to ensure timely communication of current access codes and to disable invalid or expired codes. Providing such connections may sometimes be undesirably time-consuming or expensive.
It is desirable, therefore, to provide a secure access control system that overcomes the limitations of the prior art. It is further desirable to provide new applications for access control systems, that take advantage of improvements from overcoming limitations of the prior art.